The quake, which was centered 61 miles west-northwest of Iquique, and was 6.21 miles deep, was initially measured at 8.0, but was later upgraded, the U.S. Geological Survey said.

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The Pacific Tsunami Warning Center said a six-foot tsunami hit Pisagua, Chile, at 8:04 p.m. ET. There was some damage reported on roads linking northern towns between Iquique and Alto Auspicio.

A tsunami warning for countries in the area - including Peru, Ecuador, Colombia and Panama - was canceled.

An advisory remains in effect for Hawaii, but the waves aren't expected to cause much damage, Gerard Fryer, a geophysicist at the Pacific Tsunami Warning Center, told ABC News.

"The waves will not be big enough to cause any flooding, so nobody needs to evacuate. But we just want to clear the beaches. And fortunately, since it's 3:30 in the morning, that's really no hardship," Fryer said.

“The biggest worry is the currents. If anyone is in the water, you know fishing or something like that, they could get banged up or swept out to sea or something.”

The northern part of Chile is being declared a disaster zone and armed forces are on their way to the area, President Michelle Bachelet said at an overnight press conference. The presidents of Peru and Argentina have called, lending support if needed, Bachelet said.

The earthquake was so strong that the shaking it caused in La Paz, Bolivia, 290 miles from the epicenter, was the equivalent of a 4.5-magnitude tremor, authorities there said. The quake triggered at least eight strong aftershocks in the first few hours, including a 6.2 tremor.

In Chile, evacuation orders were issued for the cities of Arica, Iquique and Antofagasta. All cities were along a low coast and each evacuation involved a significant climb to higher land further inland.

Salvador Urrutia, the mayor of Arica, said there were minor injuries in the city but no deaths reported. Some homes were damaged, but the modern structures and taller buildings were not damaged.

He said the city was without power and had no cellphone service.

Despite the fear caused by the evacuation order, which was not limited to the coast, he said people remained calm.

Evacuations were ordered along the coast in Peru. In the seaside town of Boca del Rio, waves 2 meters above normal hit the shore, but there were no injuries or major damage, Col. Enrique Blanco, the regional police chief in Tacna, a Peruvian city of 300,000 near the Chilean border, told The Associated Press.

"The lights went out briefly, but were re-established," Blanco said.

Two waves hit initially Iquique and Pisagua, but none larger than two meters.

The first wave was not necessarily the strongest, local officials said, and people were warned not to return to the coastline until alert is lifted.

There have been numerous quakes in the same area over the past few weeks, but scientists said it was not clear whether they were a sign that a major quake was coming.

A magnitude-6.7 quake rattled the area on March 16, and more than 100,000 people were briefly evacuated from low-lying areas. No tsunami resulted from that quake, which caused little damage.

In 2010, a magnitude-8.8 quake and ensuing tsunami in central Chile killed more than 500 people, destroyed 220,000 homes and caused widespread damage to docks, riverfronts and seaside resorts.

The strongest earthquake ever recorded also happened in Chile, in 1960. That magnitude-9.5 tremor killed more than 5,000 people.